This is a phenomenom where a woman wearing a g-string farts causing the thin strip of butt floss to vibrate like a reed and resonnate a sound like a duck call.A similar effect is accomplished by holding a blade of grass between cupped hands and blowing.With a little practice,a wearer can produce sounds that mimic a crow call and a dying rabbit.By adjusting thong tension and sphincter control,notes ranging between E flat and C sharp are possible.